The present invention provides improvements in dairy products especially cultured dairy products such as yogurt that themselves contain cultured dairy ingredients such as cultured whey and to methods of preparing such improved cultured dairy products and methods for preparing such cultured dairy ingredients.
The improvement resides in part in the preparation of an improved cultured dairy ingredient intermediate product such as whey and the utilization of this improved cultured whey intermediate product in the preparation and formulation of finished cultured dairy products.
Cultured dairy products such as yogurt, cottage cheese, sour cream, kefir, buttermilk, etc., often contain various specialty dairy ingredients, e.g. whey, non-fat dry milk, whey protein concentrate solids, etc. These specialty dairy products themselves can be cultured dairy ingredients. These cultured dairy ingredients are intermediate products that possess various desirable qualities such as flavor, thickening power, nutrition, specific microorganisms and other properties such as mold growth control.
In particular, extended shelf life of refrigerated cultured dairy products such as yogurt is of considerable commercial interest. Mold is an important cause of spoilage.
Cultured dairy product preparation typically involves a heat treatment to destroy undesirable organism prior to inoculation with the desired active culture.
Additionally, mold spoilage control can involve addition of components to inhibit mold growth during extended refrigerated storage. For example, a chemical preservative such as potassium sorbate or propionic acid can be added by direct addition of the active chemical. While useful, the added sorbate must be declared on the product's ingredient statement. Consumers who prefer "natural" products find inclusion of such added chemicals such as chemical preservatives as being undesirable.
Mold spoilage control can also involve the inoculation of the cultured dairy product with selected bacterial cultures that inhibit mold growth. (See, for example, U.S. Pat. No. 4,728,516 entitled "Method for the Preservation of Creamed Cottage Cheese" issued Mar. 1, 1999 to Boudreaux et al.)
Mold spoilage control can also involve adding a naturally derived non-viable, anti-microbial ingredient to the cultured dairy product. This ingredient can be declared as a natural ingredient on the finished product ingredients label.
For example, cultured whey ingredients are commercially available that contain propionic acid and these ingredients are typically used for mold growth control in baked goods. These are not usually sold for dairy products due to the premature coagulation problem solved by the present invention. Whey or other dairy ingredients are inoculated with a culture that produces propionic acid and cultured to desired acid levels and optionally dried to a powder. A good description of preparing a cultured whey is given, for example, in U.S. Pat. No. 2,465,905 (issued Mar. 29, 1949 to Meade et al.) entitled "Process of Making Whey Food Products".
During the fermentation of cultured dairy ingredients such as whey for the production of ingredients containing propionic acid, calcium hydroxide is added to neutralize the acidity resulting from fermentation. For example, by preventing the pH from dropping below 6.5, fermentation can be continued to produce higher levels of propionic acid. When the cultured whey with high propionic acid levels is dried, however, the total calcium level in the ingredient can be quite high, e.g., about 15,000 mg/100 g.
An unfortified six ounce (170 g)serving of a low fat yogurt provides only approximately 200 to 400 mg of calcium. The milk blend or milk base used to prepare yogurt is very sensitive to additional ionic calcium fortified prior to pasteurization.
The process of heat coagulation of milk proteins is not entirely understood, though experts in the field concur that ionic calcium plays an integral role. For example, the high levels of calcium in the milk base can cause undesirable premature coagulation of dairy proteins upon heat treatment prior to inoculation in the preparation of yogurt. The problem of premature coagulation of a heat treated milk base is even more severe when milk bases contains condensed milk diluted to regular strength with tap water containing dissolved calcium and magnesium. For this reason, post pasteurization and fermentation addition of calcium is taught to be useful (See for example, U.S. Pat. No. 5,820,903 entitled "Calcium Fortified Yogurt and Methods of Preparation" issued Oct. 13, 1998 to Fluery et al. which is incorporated herein by reference). Thus, addition of the desirable propionic bearing cultured whey ingredient is severely limited since even addition of even modest levels can raise calcium concentrations to levels that can cause premature coagulation. This extremely high ionic calcium level ingredient can profoundly adversely affect the preparation methods for the cultured dairy products containing the cultured dairy ingredient.
Surprisingly, the present invention provides improved cultured dairy products containing high calcium content cultured dairy ingredients that are less susceptible to premature coagulation and provides methods of preparing such improved dairy products.
The present invention further provides improved cultured dairy ingredients having high levels of calcium, especially soluble calcium, that nonetheless minimize premature coagulation of dairy proteins.
The improvement resides in part in the fortification of the cultured dairy ingredients with defined levels of calcium sequestrants especially by blending in dry form.
The present invention further provides cultured dairy ingredients having high levels of calcium, especially soluble calcium, that nonetheless minimize premature coagulation of dairy proteins, and that can contain high levels of propionic acid.
The present invention also provides methods for preparing such cultured dairy ingredients.
The present invention further provides cultured dairy products exhibiting longer refrigerated shelf life that contain cultured dairy ingredients that provide increased mold resistance.
The present invention further provides improved pasteurized milk blends that are useful in the preparation of cultured dairy products which are resistant to mold growth and which blends are resistant to premature coagulation.
The present invention further provides methods for inhibiting psychrotrophic bacteria and mold in refrigerated cultured dairy products using cultured dairy ingredients containing high levels of calcium, especially soluble calcium, and containing high levels of propionic acid.
The present invention further provides methods that are simple and economical and which are regarded as natural as opposed to chemical for the inhibition of mold growth in cultured dairy products.
The present invention also contains cultured dairy ingredients that provide increased mold resistance and that are high in highly bioavailable calcium levels to provide higher calcium nutrition and which are organoleptically superior even in the absence of an added fruit sauce.
The present invention provides cultured dairy products resistant to premature coagulation containing high calcium content cultured dairy ingredients that have been cultured with nonpropionic generating starter cultures.
These and other objects will become increasingly apparent by reference to the following description.